Phthalic acid imides as synergists for improving the properties of aqueous pigment preparations

ABSTRACT

The invention relates to pigment preparations containing (a) at least one organic or inorganic pigment; (b) at least one cyclic imide of general formula (1) wherein R 1  represents a linear-chain, branched or cyclic aliphatic radical having 10 to 30—preferably 12 to 25—carbon atoms, or an alkenyl radical having 10 to 30—preferably 12 to 25—carbon atoms, the aforementioned radicals being able to be substituted by at least one, e.g. 2, 3, 4 or 5, substituent from the group consisting of C 1 -C 6 -alkyl, C 1 -C 6 -alkoxy, C 6 -C 10 -aryl, hydroxy, carboxy, and sulfo, R 2 , R 3 , R 4  and R 5  are the same or different and represent hydrogen, C 1 -C 10 -alkyl, C 1 -C 10 -alkoxy, halogen, OR 6 , NR 6 R 7 , —COOR 6 , —CONR 6 R 7 , —NR 6 —COR 7 , SO 2 NR 6 R 7 , —SO 3 M, —NO 2 , —CN or CF 3 , R 6  and R 7  representing H or an alkyl radical having 1 to 10 C atoms and M representing an equivalent of a cation having a valency of 1 to 3; and (c) optionally further standard additives.

[0001] The present invention is situated in the field of aqueous pigmentpreparations.

[0002] In the production of preparations and dispersions of colorants,for example, disperse dyes or organic and inorganic pigments, forapplications in aqueous or organic media, a large number of nonionic,anionic, and cationic surfactants is presently in use. The incorporationof pigments or their preparations into coating systems, printing inks,plastics, and other applications is sometimes accompanied bydifficulties, since the fine and flocculation-stable dispersion ofnumerous pigments in the respective application medium is veryunsatisfactory and involves a high level of dispersing effort.Consequently, the performance properties are very often inadequate. Forinstance, during the dispersing operation and thereafter as well,flocculation phenomena and formation of sediment may occur, which leadto changes in the viscosity of the application medium, to changes inshade and to losses in color strength, opacity, gloss, homogeneity, andbrightness and also to shades which are difficult to reproduce and to anexcessive tendency for paints to run in the case of the materialscolored.

[0003] For improving the pigment properties a variety of derivatives ofpigment molecules are known which are said to enhance thedispersibility. For example, for quinacridone pigments, additives aredescribed which are based on the chemical bonding ofisoindole-1,3-diones to this pigment class. One example of this class ofcompound is the 2-(phthalimido-methyl)quinacridone U.S. Pat. No.4,478,968 describes for enhancing the dispersing properties of thequinacridone pigment.

[0004] EP-A-0 636 666 describes imide and bisimide derivatives whichderive from perylene-3,4,9,10-tetracarboxylic anhydride and are madeavailable by reaction with amines. These imides are suitable forproducing pigment preparations.

[0005] None of the products described in the cited documents above,however, is capable of decisively enhancing the fluidity and theflocculation stability of pigment dispersions without having adeleterious influence on other parameters, such as color strength,gloss, shade, and dispersibility. One of the disadvantages of theproducts described in the abovementioned documents is that the solublepigment derivatives, which are themselves intensely colored, can leadundesirably to bleeding in binder systems or in plastics and so to thestaining of adjacent materials. Moreover, owing to the low solubility ofthe parent pigments, the preparation of pigment-derived compounds ofthis kind involves difficult conditions and a high cost. A furtherdisadvantage is the limited application scope, which because of theirintrinsic color remains restricted to pigments of the same or similarcolor.

[0006] The present invention was based on the object of providingpigment preparations which are suitable for producing highly fluid,flocculation-resistant, and storage-stable colorant dispersions forexterior and interior coating and are largely free from thedisadvantages specified above.

[0007] The object stated is surprisingly achieved by addingbelow-specified nonpigmentary cyclic imides having aliphatic or olefiniccarbon chains, which are virtually colorless or only very slightlycolored, to organic or inorganic pigments.

[0008] The present invention provides pigment preparations comprising

[0009] a) at least one organic or inorganic pigment;

[0010] b) at least one cyclic imide of the general formula (1)

[0011] where

[0012] R¹ [lacuna] for a straight-chain, branched or cyclic aliphaticradical having 10 to 30, preferably 12 to 25, carbon atoms; for analkenyl radical having 10 to 30, preferably 12 to 25, carbon atoms, itbeing possible for the radicals stated to be substituted by one or more,e.g., 2, 3, 4 or 5, substituents from the group consisting of C₁-C₆alkyl, C₁-C₆ alkoxy, C₆-C₁₀ aryl, hydroxyl, carboxyl, and sulfo;

[0013] R², R³, R⁴ and R⁵ are identical or different and denote hydrogen,C₁-C₁₀ alkyl, C₁-C₁₀ alkoxy, halogen, —OR⁶, —NR⁶R⁷, —COOR⁶, —CONR⁶R⁷,—NR⁶—COR⁷, SO₂NR⁶R⁷, —SO₃M, —NO₂, —CN or CF₃, R⁶ and R⁷ standing for Hor an alkyl radical having 1 to 10 carbon atoms and M standing for oneequivalent of a 1 to 3 valent cation, e.g. hydrogen or alkali metal; and

[0014] c) if desired, further customary additives.

[0015] Compounds of the formula (1) per se are known. These compoundsare described in, for example, U.S. Pat. No. 4,992,204, but are not usedtogether with organic pigments.

[0016] U.S. Pat. No. 6,039,769 describes the use of nonpigmentary cyclicimides having short alkyl radicals for perylene pigment preparations.

[0017] Preferred imides of the formula (1) are those wherein

[0018] R¹ denotes decyl, dodecyl, tetradecyl, octadecyl, isotridecyl,lauryl, oleyl or stearyl.

[0019] Preferred imides of the formula (1) are also those wherein R²,R³, R⁴, and R⁵ are identical or different and denote hydrogen, methyl,ethyl, propyl, butyl, methoxy, ethoxy, amino, methylamino,dimethylamino, ethylamino, diethylamino, carboxyl, COOCH₃, carboxamide,CON(CH₃)₂, sulfonamide, SO₂N(CH₃)₂, sulfo, nitro, cyano or CF₃.

[0020] The compounds of the formula (1) used in the pigment preparationsof the invention can be prepared by known methods from the aromaticparent structures, preferably the cyclic anhydrides, by reaction withthe corresponding fatty amines. The cyclic anhydrides are eithercommercially available or can be prepared easily by known methods fromthe corresponding dicarboxylic acids: for example, by heating and bytreatment with strong acids or dehydrogenating reagents. Of the numerousfatty amines and the natural fatty amine mixtures, only the mostimportant will be mentioned here, such as, for example, dodecylamine,tetradecylamine, octadecylamine, isotridecylamine, coconut fatty amine,laurylamine, oleylamine, rapeseed oil fatty amine, stearylamine ortallow fatty amine. In addition to the fatty amines, mention may also bemade of resin amines, and the derivatives preparable therefrom. Thewater formed during the reaction may be removed distillatively with theaddition where appropriate of an azeotrope former: for example, ahydrocarbon or chlorohydrocarbon.

[0021] Preferably, however, the amide formation is carried out withoutsolvent simply by distillative removal of the water of reaction formed.Owing to the quantitative yields of amide there is no need for furtherpurification or treatment of the product.

[0022] Examples of organic pigments in the sense of the invention aremonoazo pigments, disazo pigments, disazo condensation pigments, lakedazo pigments, triphenylmethane pigments, thioindigo pigments, thiazineindigo pigments, perylene pigments, perinone pigments, anthanthronepigments, diketopyrrolopyrrole pigments, dioxazine pigments,quinacridone pigments, phthalocyanine pigments, isoindolinone pigments,isoindoline pigments, benzimidazolone pigments, naphthol pigments andquinophthalone pigments, preference being given to anthanthronepigments, dioxazine pigments, and phthalocyanine pigments, and also acidto alkaline carbon blacks from the group of the furnace blacks or gasblacks.

[0023] Examples of suitable inorganic pigments are titanium dioxides,zinc sulfides, iron oxides, chromium oxides, ultramarine, nickel andchromium antimony titanium oxides, cobalt oxides, and bismuth vanadates.

[0024] Preferred pigment preparations contain

[0025] a) 5 to 60% by weight, especially 10 to 50% by weight, ofpigment;

[0026] b) 0.1 to 15% by weight, especially 0.5 to 10% by weight, of theimide of the formula (1);

[0027] c) 0 to 50% by weight, especially 1 to 30% by weight, of furtheradditives; and

[0028] d) 10 to 80% by weight of water, based on the total weight of thepigment preparation.

[0029] Examples of further additives are anionic, cationic or nonionicsurfactants, foam-reducing agents, agents which prevent the preparationdrying out, and preservatives.

[0030] Suitable surfactants include all known anionic, cationic, andnonionic surface-active compounds. Surfactants which possess one or moremedium- or long-chain hydrocarbon chains have proven themselvesparticularly. Of the multiplicity of compounds only a selection will belisted at this point, without, however, restricting the applicability ofthe compounds of the invention to these examples. Examples are alkylsulfates, alkenyl sulfates, alkylsulfonates, alkenylsulfonates, alkylphosphates, alkyl-benzenesulfonates, such as lauryl sulfate, stearylsulfate, dodecyl-sulfonates, octadecyl sulfates, dodecylsulfonates;condensation products of fatty acid and taurine or hydroxyethanesulfonicacid, alkoxylation products of alkylphenols, castor oil rosin esters,fatty alcohols, fatty amines, fatty acids, and fatty acid amides,especially reaction products of nonylphenol and relatively short-chain,substituted alkylphenols and also their polymeric derivatives, e.g.,formaldehyde condensation products.

[0031] The use of surfactants having identical or very similar aliphaticradicals to prepare the pigment dispersions of the invention givesdispersions having particularly good and application-friendlyproperties.

[0032] The present invention also provides a process for producing thepigment preparations of the invention by adding the compound(s) of theformula (1) and, where appropriate, the further additives during thepigment synthesis, or during one of the customary finishing steps suchas grinding, dispersing or solvent treatment or else not until duringthe incorporation of the pigment into the application medium. Thecompound of the formula (1) can be added in solid or dissolved form tothe pigment, which is present as a solid or as a dispersion in water oran organic solvent.

[0033] Dispersing and grinding operations take place conventionally inaccordance with the hardness of the pigment used: for example, insawtooth stirrers (dissolvers), rotor-stator mills, turbulent high-speedmixers, ball mills, sand mills or bead mills, in kneading apparatus oron roll mills.

[0034] The liquid- to pastelike pigment preparations prepared in thisway are available for any purpose for which colorant dispersions arenormally employable and for which exacting requirements are imposed onflocculation and/or storage stability, changes in viscosity of theapplication medium, shade changes, color strength, opacity, gloss,homogeneity, and brightness. Thus they are suitable, for example, forthe coloring of natural and synthetic materials. They are particularlyvaluable, in accordance with the invention, for the preparation ofpaints and/or printing inks, and also for the coloring of plastics andhigh molecular mass materials, but preferably for the preparation ofpigment dispersions which further comprise one or more surfactants,water, customary amounts of builder substances or other customaryadditives or auxiliaries which are used in emulsifying and dispersingformulations, such as, for example, additives which delay theformulation drying out. Aqueous dispersions prepared on this basis areoutstandingly suitable for pigmenting both hydrophilic and hydrophobicsystems.

[0035] As well as the preparation of pigment dispersions the compoundsof the invention can also be used, preferably in combination withsurfactants, to prepare dispersions of dyes, optical brighteners, andalso for formulating crop protection and pesticide compositions andadditionally as emulsifying, leveling, and dyeing assistants for thedyeing of natural and synthetic fiber materials.

[0036] The pigment dispersions of the invention are suitable ascolorants in electrophotographic toners and developers, such as one- ortwo-component powder toners (also called one- or two-componentdevelopers), magnetic toners, liquid toners, latex toners,polymerization toners, and specialty toners, for example.

[0037] Typical toner binders are addition polymerization, polyadditionand poly-condensation resins, such as styrene, styrene-acrylate,styrene-butadiene, acrylate, polyester, phenolic-epoxy resins,polysulfones, polyurethanes, individually or in combination, and alsopolyethylene and polypropylene, which may include further ingredients,such as charge control agents, waxes or flow assistants, or may bemodified subsequently with these additives.

[0038] Furthermore, the pigment dispersions of the invention aresuitable as colorants in powders and powder coating materials,especially in triboelectrically or electrokinetically sprayable powdercoating materials, which are used to coat the surfaces of articles made,for example, of metal, wood, plastic, glass, ceramic, concrete, textilematerial, paper or rubber.

[0039] Typical powder coating resins used include epoxy resins,carboxyl- and hydroxyl-containing polyester resins, polyurethane resins,and acrylic resins, together with customary curatives. Resincombinations are also employed. For example, epoxy resins are frequentlyused in combination with carboxyl- and hydroxyl-containing polyesterresins. Typical curative components (depending on the resin system) are,for example, acid anhydrides, imidazoles and also dicyandiamide and itsderivatives, blocked isocyanates, bisacylurethanes, phenolic resins andmelamine resins, triglycidyl isocyanurates, oxazolines, and dicarboxylicacids.

[0040] In addition, the pigment dispersions of the invention aresuitable as colorants in inks, preferably ink-jet inks, such as those onan aqueous or nonaqueous basis, for example, in microemulsion inks, andin those inks which operate in accordance with the hot-melt process.

[0041] Ink-jet inks generally contain in total from 0.5 to 15% byweight, preferably 1.5 to 8% by weight (calculated on a dry basis), ofthe pigment dispersions of the invention.

[0042] Microemulsion inks are based on organic solvents, water, and,where appropriate, an additional hydrotropic substance (interfacemediator). Microemulsion inks contain 0.5 to 15% by weight, preferably1.5 to 8% by weight, of the pigment dispersions of the invention, 5 to99% by weight of water, and 0.5 to 94.5% by weight of organic solventand/or hydrotropic compound.

[0043] Solvent-based ink-jet inks contain preferably 0.5 to 15% byweight of the pigment dispersions of the invention, 85 to 99.5% byweight of organic solvent and/or hydrotropic compounds.

[0044] Hot-melt inks are based generally on waxes, fatty acids, fattyalcohols or sulfonamides which are solid at room temperature and becomeliquid on heating, the preferred melting range being situated betweenabout 60 and about 140° C. Hot-melt ink-jet inks consist essentially,for example, of 20 to 90% by weight of wax and 1 to 10% by weight of thepigment dispersions of the invention. Furthermore, 0 to 20% by weight ofan additional polymer (as “dye dissolver”), 0 to 5% by weight ofdispersing auxiliary, 0 to 20% by weight of viscosity modifier, 0 to 20%by weight of plasticizer, 0 to 10% by weight of tack additive, 0 to 10%by weight of transparency stabilizer (prevents, for example,crystallization of the waxes), and 0 to 2% by weight of antioxidant maybe present. Typical additives and auxiliaries are described in, forexample, U.S. Pat. No. 5,560,760.

[0045] Moreover, the pigment dispersions of the invention are alsosuitable as colorants for color filters, both for additive and forsubtractive color generation, and for “electronic inks”.

[0046] The pigment dispersions prepared in accordance with the inventionare miscible with water in any proportion as compared with conventionalpigment dispersions feature an outstanding flocculation stability andstorage stability in numerous aqueous emulsion paints. Where surfactantscompatible with hydrophobic film-forming binder systems are used inpreparing the pigment dispersions, it is also possible to preparedispersions which are stable to flocculation in hydrophobic media.Particularly noteworthy features include the good rheological propertiesand also the excellent dispersibility in different application media.

[0047] The compounds of the invention therefore make it possible,preferably in combination with an appropriate surfactant, to achievevirtually the full color strength and brightness of pigments during thedispersing operation and to stabilize these qualities lastingly in theapplication medium. Pale and bright shades are unaffected by the minimalintrinsic coloration of the compounds.

[0048] In the examples which follow, percentages and parts are byweight.

1. Aqueous Preparation Comprising a Violet Pigment (C.I. Pigment Violet23)

[0049] Preparation A

[0050] 1.1 Comparative Preparation Without Synergist

[0051] In order to evaluate the compounds of the invention, apreparation without synergist is prepared first of all. This preparationis then incorporated by stirring both into a white dispersion and intothe varnish system, and used for coloring. These colorations serve as astandard with which the novel preparations are compared.

[0052] Ingredients:

[0053] 20% C.I. Pigment Violet 23

[0054] 21% mixture of nonionic dispersants (polyphenol/fatty alcoholethoxylate)

[0055] 1% mixture of long-chain fatty acids

[0056] 10% glycerol

[0057] 10% propylene glycol

[0058] 0.2% preservative

[0059] 37.8% demineralized water

[0060] To produce the pigment preparations, first of all the liquidingredients are homogenized in a laboratory beadmill in analogy to theformulas set out in the examples. Using a sawtooth disk, the pulverulentpigment is then incorporated and the amount of water chosen here is suchas to give a paste which is homogeneous, of relatively high viscosity,and readily stirrable. Subsequently the grinding medium (1 mmsiliquartzite beads) is added and the paste is ground for 60 minutes.After the grinding medium has been mixed in initially at the beginningof grinding, the optimum milling viscosity is set appropriately byadding water. After grinding, the grinding medium is separated off bycentrifugation.

[0061] For suitability testing, this pigment preparation is stirred at aconcentration of 1% into a commercially available standard whitedispersion, applied as a thin film and then subjected to coloristicevaluation.

[0062] Incorporation also takes place into a test varnish in order toassess the varnish compatibility of the pigment preparation. As well asthe incorporation of the pigment preparation into the test varnish bystirring with a spatula for about 10 minutes, an analogous sample isprepared by stirred incorporation for about 10 minutes using a dissolverdisk. The two samples are compared with one another in terms of colorstrength. In this comparison, figures close to 100% indicate excellentdispersing and high paint compatibility of the pigment preparation.

[0063] In order to test the dispersibility and the flocculationstability in the application medium, a part of the film is subjected tobrief initial drying and then rubbed repeatedly under moderate pressurewith a brush or with the finger. If the pigment preparation is dispersedunsatisfactorily in the test medium or if flocculation occurred duringincorporation of the preparation into the test medium, then the shearingforce exerted on the film by rubbing causes at least partialdeflocculation or deagglomeration of flocculated or agglomerated pigmentparticles. The area treated in this way then exhibits either a highercolor strength and/or a more irregular or unequal shade in comparisonwith the unrubbed area. The rubout test is suitable as a simple butusually very sensitive test for assessing with relative ease the qualityof the pigment preparation in terms of dispersibility and offlocculation stability. A test of this kind is widely described in theliterature; for example, in FARBE & LACKE 100, number 6/2000, 51-61.

[0064] To test the storage stability, a sample of the pigmentpreparation is stored hot at 50-60° C. in a closed vessel for 4 to 5weeks. The viscosity of the samples is measured both before and afterthis storage. In the case of the preparation without synergist severerubout effects were evident; that is, the rubbed area of the colorationsexhibits a relatively high color strength and also severe irregularitiesin shade. Moreover, the preparations thicken both at room temperatureand at 50-60° C. within a few days to form a solid mass which can nolonger be liquefied even by stirring or shaking and which from aperformance standpoint can no longer be utilized as a pigmentpreparation.

[0065] 1.2 Preparation with Synergist 1

[0066] Preparation of the Synergist 1:

[0067] 74.06 parts of phthalic anhydride and 133.75 parts of oleylamineare mixed at room temperature and heated at 130° C. for 4 hours under anitrogen atmosphere with stirring. The water of reaction formed isdistilled off continuously.

[0068] Production of the Pigment Preparation:

[0069] 20% C.I. Pigment Violet 23

[0070] 21% mixture of nonionic dispersants (polyphenol/fatty alcoholethoxylate)

[0071] 2% synergist 1

[0072] 1% mixture of long-chain fatty acids

[0073] 10% glycerol

[0074] 10% propylene glycol

[0075] 0.2% preservative

[0076] 35.8%demineralized water

[0077] The pigment preparation is produced as described in Example 1.1but with the use of the above formula and of the above-describedsynergist 1. For suitability testing, 1% of this pigment preparation isstirred into commercially available standard white dispersion, appliedas a thin film and then subjected to coloristic evaluation. It was alsoincorporated into a test varnish in order to assess the varnishcompatibility of the pigment preparation. As well as being incorporatedinto the test varnish by stirring with a spatula for about 10 minutes,an analogous sample of the pigment preparation is prepared by stirredincorporation with a dissolver disk for about 10 minutes. The twosamples are compared with one another in terms of color strength (HSdispersion).

[0078] In order to test the dispersibility and the flocculationstability in the application medium, a part of the film is subjected tobrief initial drying and then rubbed repeatedly under moderate pressurewith a brush or with the finger (rubout test).

[0079] Results: rel. color strength (matt, 1%): 107%, dC = 1.36 (IIIcleaner), dH = −0.32 (II bluer, dE = 1.4 rel. color strength (varnish,103%, dC = −0.32 (II dirtier), 1%): dH = −0.49 (II bluer), dE = 0.59 HSdispersion: 106% Viscosity (fresh): 911.9 mPas Viscosity (4 weeks/50°C.): 1554.0 mPas

[0080] The pigment preparation produced in accordance with the inventionis found to be stable on storage; that is, despite hot storage at 50° C.for 4 weeks, the sample remained very fluid. The hand stirrer (HS)dispersion of only 106% is evidence of the excellent dispersing and highvarnish compatibility of the pigment preparation. In the case of thepreparation there were no rubout effects at all; that is, the rubbedarea of the colorations has an identical color strength and noirregularities in shade. The testing of this pigment preparation incommercially available standard white dispersion produces not only thedistinct color strength gain but also a significantly cleaner shade ascompared with the preparation without the synergist of the invention.

[0081] 1.3 Preparation with Synergist 2

[0082] Preparation of the Synergist 2:

[0083] As in Example 1.2 from 74.06 parts of phthalic anhydride and131.0 parts of tallow fatty amine.

[0084] Production of the Pigment Preparation:

[0085] The pigment preparation is produced as described in Example 1.1but using the above synergist 2 and the formula given under Example 1.2,and is tested as described above.

[0086] Results: rel. color strength (matt, 1%): 105%, dC = 1.07 (IIIcleaner), dH = −0.32 (II bluer), dE = 1.12 rel. color strength (varnish,1%):  97%, dC = −0.46 (II dirtier), dH = −0.40 (II bluer), dE = 0.61 HSdispersion: 106% Viscosity (fresh):  839.6 mPas Viscosity (4 weeks/50°C.): 1032.0 mPas

[0087] The pigment preparation produced in accordance with the inventionis found to be outstandingly stable on storage; that is, despite hotstorage at 50° C. for 4 weeks, the sample remained very fluid. In thecase of the preparation there were no rubout effects at all; that is,the rubbed area of the colorations has an identical color strength andno irregularities in shade. The testing of this pigment preparation incommercially available standard white dispersion produces not only thedistinct color strength gain but also a significantly cleaner shade ascompared with the preparation without the synergist of the invention.

[0088] 1.4 Preparation with Synergist 3

[0089] Preparation of the Synergist 3:

[0090] As in Example 1.2 from 58.5 parts of phthalic anhydride and 106.5parts of octadecylamine (95% form).

[0091] Production of the Pigment Preparation:

[0092] The pigment preparation is produced as described in Example 1.1but using the above synergist 3 and the formula given under Example 1.2,and is tested as described above.

[0093] Results: rel. color strength (matt, 1%): 108%, dC = 1.35 (IIIcleaner), dH = −0.30 (II bluer), dE = 1.39 rel. color strength (varnish,96%, dC = −0.69 (III dirtier), 1%): dH = −0.44 (II bluer), dE = 0.82 HSdispersion: 106% Viscosity (fresh): 683.7 mPas Viscosity (4 weeks/50°C.): 1034.0 mPas

[0094] The pigment preparation produced in accordance with the inventionis found to be outstandingly stable on storage; that is, despite hotstorage at 50° C. for 4 weeks, the sample remained very fluid. In thecase of the preparation there were no rubout effects at all; that is,the rubbed area of the colorations has an identical color strength andno irregularities in shade. The testing of this pigment preparation incommercially available standard white dispersion produces not only thedistinct color strength gain but also a significantly cleaner shade ascompared with the preparation without the synergist of the invention.

2. Aqueous Preparation Comprising C.I. Pigment Violet 23

[0095] Preparation B

[0096] 2.1 Comparative Preparation Without Synergist

[0097] In order to evaluate the compounds of the invention a preparationwithout synergist is prepared first of all. This preparation is thenincorporated by stirring into a white dispersion, and used for coloring.These colorations serve as a standard with which the novel preparationsare compared.

[0098] Ingredients:

[0099] 30% C.I. Pigment Violet 23

[0100] 12% mixture of nonionic dispersants (polyphenol/fatty alcoholethoxylate)

[0101] 20.0% propylene glycol

[0102] 0.2% preservative

[0103] 37.8% demineralized water

[0104] Production and Suitability Testing of the Pigment Preparation asDescribed Under 1.1.

[0105] In the case of the preparation without synergist severe rubouteffects were evident; that is, the rubbed area of the colorationsexhibits a relatively high color strength and also severe irregularitiesin shade. Moreover, the preparations thicken both at room temperatureand at 50-60° C. within a few days to form a solid mass which can nolonger be liquefied even by stirring or shaking and which from aperformance standpoint can no longer be utilized as a pigmentpreparation.

[0106] 2.2 Preparation with Synergist 2

[0107] Preparation of the Synergist 2:

[0108] As in Example 1.2 from 74.06 parts of phthalic anhydride and133.75 parts of oleylamine.

[0109] Ingredients of the Pigment Preparation:

[0110] 30% C.I. Pigment Violet 23

[0111] 12% mixture of nonionic dispersants (polyphenol/fatty alcoholethoxylate)

[0112] 4% synergist 2

[0113] 20.0% propylene glycol

[0114] 0.2% preservative

[0115] 33.8% demineralized water

[0116] Results: rel. color strength (matt, 1%): 101%, dC = 0.43 (IIcleaner), dH = −0.12 (I bluer), dE = 0.45 Viscosity (fresh): 762.1 mPasViscosity (4 weeks/50° C.): 800.0 mPas

[0117] The pigment preparation produced in accordance with the inventionis found to be outstandingly stable on storage; that is, despite hotstorage at 50° C. for 4 weeks, the sample remained very fluid. In thecase of the preparation there were no rubout effects at all; that is,the rubbed area of the colorations has an identical color strength andno irregularities in shade. The testing of this pigment preparation incommercially available standard white dispersion also produces asignificantly cleaner shade as compared with the preparation without thesynergist of the invention.

[0118] The synergist of the invention also improves the grindingcharacteristics positively. Whereas without synergist the temperature ofthe pigment preparation during grinding should not rise substantiallyabove 25° C. in order to prevent thickening, the preparation withsynergist can be ground at 60° C. until the target color strength isreached. No substantial deterioration is observed in the coloristic dataas compared with grinding at 25° C.

3. Aqueous Preparation Comprising a Red Pigment (C.I. Pigment Red 168)

[0119] 3.1 Comparative Preparation Without Synergist

[0120] In order to evaluate the compounds of the invention a preparationwithout synergist is prepared first of all. This preparation is thenincorporated by stirring into a white dispersion, and used for coloring.These colorations serve as a standard with which the novel preparationsare compared.

[0121] Ingredients:

[0122] 35% C.I. Pigment Red 168

[0123] 10% mixture of nonionic dispersants (fatty alcohol ethoxylates)

[0124] 10.0% propylene glycol

[0125] 10.0% diethylene glycol

[0126] 0.2% preservative

[0127] 34.8% demineralized water

[0128] Production and Suitability Testing of the Pigment Preparation asDescribed under 1.1.

[0129] In the case of the preparation without synergist severe rubouteffects were evident; that is, the rubbed area of the colorationsexhibits a relatively high color strength and also severe irregularitiesin shade. Moreover, the preparations thicken both at room temperatureand at 50-60° C. within a few days to form a solid mass which can nolonger be liquefied even by stirring or shaking and which from aperformance standpoint can no longer be utilized as a pigmentpreparation.

[0130] 3.2 Preparation with Synergist 2

[0131] Preparation of the Synergist 2:

[0132] As in Example 1.2 from 74.06 parts of phthalic anhydride and133.75 parts of oleylamine.

[0133] Ingredients of the Pigment Preparation:

[0134] 35% C.I. Pigment Red 168

[0135] 10% mixture of nonionic dispersants (fatty alcohol ethoxylates)

[0136] 4% synergist

[0137] 10.0% propylene glycol

[0138] 10.0% diethylene glycol

[0139] 0.2% preservative

[0140] 30.8% demineralized water

[0141] Results: rel. color strength 105%, dC = 0.58 (II cleaner), (matt,3%): dH = 0.41 (II yellower), dE = 0.76 rel. color strength (var- 100%,dC = 0.15 (I cleaner), nish, 3%): dH = −0.04 (I = I), dE = 0.16Viscosity (fresh): 209.0 mPas Viscosity (4 weeks/50° C.): 316.7 mPas

[0142] The pigment preparation produced in accordance with the inventionis found to be outstandingly stable on storage; that is, despite hotstorage at 50° C. for 4 weeks, the sample remained very fluid. In thetesting of the preparations (3% form, white dispersion, and varnish)there were no rubout effects at all; that is, the rubbed area of thecolorations has an identical color strength and no irregularities inshade. The testing of this pigment preparation in commercially availablestandard white dispersion and in the varnish system also produces asignificantly cleaner shade as compared with the preparation without thesynergist of the invention. The synergist of the invention also improvesthe grinding characteristics positively. Whereas without synergist thetemperature of the pigment preparation during grinding should not risesubstantially above 25° C. in order to prevent thickening, thepreparation with synergist can be ground at 60° C. until the targetcolor strength is reached. No substantial deterioration is observed inthe coloristic data as compared with grinding at 25° C.

4. Aqueous Preparation Comprising a Green Pigment (C.I. Pigment Green 7)

[0143] 4.1 Comparative Preparation Without Synergist

[0144] In order to evaluate the compounds of the invention a preparationwithout synergist is prepared first of all. This preparation is thenincorporated by stirring into a white dispersion, and used for coloring.These colorations serve as a standard with which the novel preparationsare compared.

[0145] Ingredients:

[0146] 45% C.I. Pigment Green 7

[0147] 8% mixture of nonionic dispersants (fatty alcohol ethoxylates)

[0148] 19.0% diethylene glycol

[0149] 0.2% preservative

[0150] 27.8% demineralized water

[0151] Production and Suitability Testing of the Pigment Preparation asDescribed under 1.1.

[0152] In the case of the preparation without synergist severe rubouteffects were evident; that is, the rubbed area of the colorationsexhibits a relatively high color strength and also severe irregularitiesin shade. Moreover, the preparations thicken both at room temperatureand at 50-60° C. within a few days to form a solid mass which can nolonger be liquefied even by stirring or shaking and which from aperformance standpoint can no longer be utilized as a pigmentpreparation.

[0153] 4.2 Preparation with Synergist 2

[0154] Preparation of the Synergist 2:

[0155] As in Example 1.2 from 74.06 parts of phthalic anhydride and133.75 parts of oleylamine.

[0156] Ingredients:

[0157] 45% C.I. Pigment Green 7

[0158] 8% mixture of nonionic dispersants (fatty alcohol ethoxylates)

[0159] 3% synergist

[0160] 19.0% diethylene glycol

[0161] 0.2% preservative

[0162] 24.8% demineralized water

[0163] Results: rel. color strength (matt, 1%): 105%, dC = −0.33 (IIdirtier), dH = 0.41 (II bluer), dE = 0.54 rel. color strength (var-105%, dC = 0.22 (I cleaner), nish, 1%): dH = −0.07 (I = I), dE = 0.24Viscosity (fresh): 305.5 mPas Viscosity (4 weeks/50° C.): 712.1 mPas

[0164] The pigment preparation produced in accordance with the inventionis found to be outstandingly stable on storage; that is, despite hotstorage at 50° C. for 4 weeks, the sample remained very fluid. In thetesting of the preparations (1% form, white dispersion, and varnish)there were no rubout effects at all; that is, the rubbed area of thecolorations has an identical color strength and no irregularities inshade. The testing of this pigment preparation in a commerciallyavailable varnish system also produces a cleaner shade as compared withthe preparation without the synergist of the invention. The synergist ofthe invention also improves the grinding characteristics positively.Whereas without synergist the temperature of the pigment preparationduring grinding should not rise substantially above 25° C. in order toprevent thickening, the preparation with synergist can be ground at 60°C. until the target color strength is reached. No substantialdeterioration is observed in the coloristic data as compared withgrinding at 25° C.

1) A pigment preparation comprising a) at least one organic or inorganicpigment; b) at least one cyclic imide of the general formula (1)

where R¹ stands for a straight-chain, branched or cyclic aliphaticradical having 10 to 30 carbon atoms; for an alkenyl radical having 10to 30 carbon atoms, it being possible for the radicals stated to besubstituted by one or more substituents from the group consisting ofC₁-C₆ alkyl, C₁-C₆ alkoxy, C₆-C₁₀ aryl, hydroxyl, carboxyl, and sulfo;R², R³, R⁴ and R⁵ are identical or different and denote hydrogen, C₁-C₁₀alkyl, C₁-C₁₀ alkoxy, halogen, —OR⁶, —NR⁶R⁷, —COOR⁶, —CONR⁶R⁷,—NR⁶—COR⁷, SO₂NR⁶R⁷, —SO₃M, —NO₂, —CN or CF₃, R⁶ and R⁷ standing for Hor an alkyl radical having 1 to 10 carbon atoms and M standing for oneequivalent of a 1 to 3 valent cation; and c) if desired, furthercustomary additives. 2) The pigment preparation of claim 1,characterized in that R¹ denotes decyl, dodecyl, tetradecyl, octadecyl,isotridecyl, lauryl, oleyl or stearyl. 3) The pigment preparation ofclaim 1 or 2, characterized in that R², R³, R⁴ and R⁵ are identical ordifferent and denote hydrogen, methyl, ethyl, propyl, butyl, methoxy,ethoxy, amino, methylamino, dimethylamino, ethyl-amino, diethylamino,carboxyl, COOCH₃, carboxamide, CON(CH₃)₂, sulfonamide, SO₂N(CH₃)₂,sulfo, nitro, cyano or CF₃. 4) The pigment preparation of at least oneof claims 1 to 3, characterized in that the organic pigment a) is amonoazo pigment, disazo pigment, disazo condensation pigment, laked azopigment, triphenyl-methane pigment, thioindigo pigment, thiazine indigopigment, perylene pigment, perinone pigment, anthanthrone pigment,diketopyrrolopyrrole pigment, dioxazine pigment, quinacridone pigment,phthalocyanine pigment, isoindolinone pigment, isoindoline pigment,benzimidazolone pigment, naphthol pigment or quinophthalone pigment, orcarbon black. 5) The pigment preparation of at least one of claims 1 to4, comprising a) 5 to 60% by weight, especially 10 to 50% by weight, ofpigment; b) 0.1 to 15% by weight, especially 0.5 to 10% by weight, ofthe imide of the formula (1); c) 0 to 50% by weight, especially 1 to 30%by weight, of further additives; and d) 10 to 80% by weight of water,based on the total weight of the pigment preparation. 6) The pigmentpreparation of at least one of claims 1 to 5, characterized in that thefurther additive is an anionic, cationic or nonionic surfactant. 7) Thepigment preparation of claim 6, characterized in that the surfactant isa compound selected from the group consisting of alkyl sulfates, alkenylsulfates, alkylsulfonates, alkenylsulfonates, alkyl phosphates,alkylbenzenesulfonates; condensation products of fatty acid and taurineor hydroxyethanesulfonic acid; alkoxylation products of alkylphenols,castor oil rosin esters, fatty alcohols, fatty amines, fatty acids, andfatty acid amides. 8) A process for preparing a pigment preparation ofat least one of claims 1 to 7, characterized in that the compound of theformula (1) is added to the pigment during its synthesis, grinding,dispersing and/or finishing. 9) Use of a pigment preparation of one ormore of claims 1 to 7 as a colorant for preparing paints, varnishes,printing inks, electrophotographic toners and developers, powder coatingmaterials, other inks, and for coloring plastics.